Internal-combustion engine



F. H. ROYCE June 11, 1929.

INTERNAL COMBUSTI ON ENGINE Filed Jan. 8, 1926 3 Sheets-Sheet June 11, 1929.

F. H. ROYCE INTERNAL COMBUSTI ON ENGINE Filed Jan. 8, 1926 3 Sheets-Sheet Junell,l929. F H ROYCE L71Z068 INTERNAL COMBUSTION ENGINE Filed Jan 8, 1926 3 Sheets-Sheet 3 Patented June 11, 1929.

UNITED STATES PATENTII OFFICE.

FREDERICK HENRY ROYCE, OF WEST- WITTERING, NEAR CHICHESTER, ENGLAND, ASSIGNOR TO ROLLS-BOYCE LIMITED, F DERBY, ENGLAND.

INTERNAL-COMBUSTION- ENGINE.

Application filed January 8, 1926, Serial No.

This invention has reference to multicylinder internal combustion engines of the type in which the cylinders are arranged in rows.

In such engines the shaft is subjected to bending strains, and great strains are put on the shaft bearings and the case, due to the inertia of the reciprocating and rotating masses and the firing impulses and many g forms of engines have been adopted with Various arrangements of cylimlers and forms of shaft with a view to balancing opposing forces, and removing or eliminating the strains referred to, but only with partial success, and in most of such engines the form of shaft adopted is not the most suitable for withstanding torsionalstrain.

The object of this invention is to construct an engine in which there is secured better 20. than by any method heretofore proposed an even distribution and a balancing of forces on the shaft to the relief of the strains re ferred to. The most powerful practical internal combustion engines heretofore made have 12 cylinder engines in two rows of six, the axes of those of one row being inclined to the axes of those of the other row as the arms of the letter V.

Experience in endeavoring to make more powerful engines have shown a tendency for the crank shaft case to give way under the strain unless made unduly heavy; and hence efforts vhave been made to overcome the difliculty by reducing the strain on the case, and for this purpose to shorten the shaft and cause the firing impulses and the inertia forces of the reciprocating masses to balance one another, and so relieve the strain on the bearings. It has been proposed to construct engines with the cylinders in shorter rows say 12 cylinders in three rows, or 16 cylinders in four rows, and with a four throw crank shaft having the throws thereon in one plane, the two centre throws being on one si'deof the shaft and the two end throws on the other side, and in the case of a 16 cylinder engine to fire the cylinders in pairs, thecylinders of each pair.

being on opposite sides of the shaft. But an engine qonstructed with a four throw crank shaft of that shape causes a severe strain on't e centre bearing owing to the 80,074, and in Great Britain January 9, 1925.

fact that the two central reciprocating masses are then reciprocating in unison. Further it has been proposed by me to construct an engine with the cylinders arranged in rows of four, with a four throw crank shaft in one plane, the throws being arranged on opposite sides of the shaft alternately, with end balance weights to coun ter the couple caused by such a shaft.

An engine constructed according to this invention comprises a new combination of shaft, cylinder arrangement, and firing se' quence. It has four rows of cylinders equispaced around the shaft each row' consisting of four cylinders, a four-throw shaft, the throws being in one plane, and reckoning from either end to the other arranged alternately on opposite sides of the shaft, and havingiend balance weights and the cylinders are arranged to be firedin pairs, all the cylinders being fired for two revolutions,

the engine being a four cycle engine, preferably one of the cylinders of each simultaneously firing pair being on one side of the shaft and the other on the opposite side, and preferably such two cylinders being on juxta-posed throws.

To eliminate or reduce to a minimum the out of balance couple caused by the form' of the crank shaft, balance weights are se' cured one at each end of the shaft, or on the end throws, the centre of gravity of each weight being in the same plane as the contiguous throw and on the opposite side of the shaft. f

Preferably of the four connecting rods operating on one throw two -(operated by two of the cylinders whose axes are at an angle of 90 to one another) are interlocked and located on one half of the throw while the other two connecting rods are likewise interlocked and located on the other half "of the throw and the first-and latter two cylinders are staggered in -irelation to one another.

Preferably also the cylinders are arranged so that their axes are 45 out of the vertical and are staggered so that of the eight upper cylinders four are shifted away from the other four while of the eight lower ones' four are shifted toward the other four, that with bifurcated ends 2 and 3- are spaced apart farther than the cylinders 1 and 2 or 3' and 4, and of the cylinders C and D the cylinders 2 and 3 are spaced apart a less distance than the cylinders 1 and 2 or 3 and 4.

Figs. 1 and 2 show diagralmnatic sectional views of the engine, Fig. 1 being a section on line 1-1 of Fig. 2; Fig. 3 is a cross section view of four rods on one crank (for example on section line 3-3 of Fig. 1). Fig. 4 is a section on line 4.4 of Fig. 3 through the axis of the crank shaft also showing four big ends on one throw. Fig. 5 is an elevation of the crankshaft, Figure 6 a diagrammatic end view of the engine showing the crankshaft. Figures 7, 8, 9, and 10 indicate the order of firing, in the case where the engine viewed from the left is driven clock-wise, and Figures 11, 12, 13 and 14 the like where the engine is driven anti-clockwise. Fig. 15 is a diagrammatical end view of the engine showing two magnetos and Fig. 16 is diagrammatical view of one magneto showing the primary winding, make and break device and condenser, and the secondary winding rotary contact blades and terminals.

- a is the case, a 'the end bearing, a are webs across the case supporting bearings a. b is the shaft, 6 are throws. A are cylinders constituting one row B another row G a third row and D the fourth row. 0 and c are the big end of two connecting rods operated by pistons of the second cylinders of rows C and D and c and c are the big ends of two connecting rods of pistons of the first cylinders of rows A and B. The big ends of the connecting rods 0 and 0 are bifurcated and those of 0 and 0 are mounted between the forks thereof. The big ends on each of the other throws are similarly arranged. v .staggered in relation to the The cylinders of one row are opposite row in manner shown in Fig. 1. 4 Referring to Figs. 3 and 4 which illustrate an example of the arrangement of the big ends on all the throws at are connecting rods 0 and c, and corresponding caps secured by means of bosses d and bolts d in the usual manner. Each of these ends is bolted to and carries with it the steel bush d which is lined internally throughout and externally between the bifurcations with white metal, e are connecting rods with simple big end and caps secured in like manner to and rocking on the steel bushes between the bifurcations. fare balance weights.

Referring to Figures 5 and 6 t t t 'and t indicate the respective throws of the crankshaft. Figure 7 represents figuratively t l 1 e cylinders No. 1 of each row and throw t ,to which the corresponding connecting rods are attached, the letters A, B, C and D represent the cylinders of the various rows,

big ends of connecting and the Figures 8, 9 and 10 similarly represent respectively the cylinders 2, 3 and 4: and throws at, and t. The numbers outside the cylinders indicate the sequence of firing the cylinders in pairs.

Figures 11, 12, 13 and 14 are similar to Figures 7, 8, 9 and 10 except that the sequence of firing is given for an engine where the shaft is to rotate in the reverse direction. Referring to Figs. 15 and 16 g are two magnetos driven by spindle kl, skew wheel 9 skew wheel 9 mounted on the crankshaft. The ignition system is duplicated entirely to provide against failure, hence either magneto will drive the engine. 12. is the primary winding 72. the condenser, and k the make and break contact. '5 is the secondary winding one end of which is connected through a brush to spindle i and contact blade 11 and the other end to spindle 2' and contact bladed. One blade makes contact with 8 terminals connected to 8 cylinders and the other to 8 terminals connected to the other 8 cylinders moving in the direction' of the arrows. The letters around the circles indicate the cylinders to which the terminals are connected.

The engine being a four cycle engine, the firing is arranged to fire all the cylinders for two revolutions.

With an, engine constructed as above the impulses communicated to the shaft are balanced and the bending strains on the shaft strains on the bearings, and hence on the case, are reduced with the result that the speed can be increased, and the weight and the size reduced in relation to the h. p. attained.

What I claim 1. An internal combustion engine comprising a four-throw crank shaft having the throws thereof in one plane and projecting alternately on opposite sides of the shaft, balance weights on each of the end throws of said shaft, the center of gravity of each balance weight being on the side of the shaft opposite to the adjacent end throw, four rows of cylinders equi-spaced around the crank shaft and each provided with a piston slidable therein, connecting rods connecting the first, second, third, and fourth pistons of each throw, respectively, to the first, second, third and fourth throws, and means for firing the cylinders in pairs in two revolutions.

2. An internal combustion engine comprising a four-throw crank shaft having the throws thereof in one plane and projecting alternately on opposite sides of the shaft, balance weights on each of the end throws of saidshaft, the center of gravity of each balance weight being on the side of the shaft opposite to the adjacent end throw, four rows of cylinders equi-spaced around the crank shaft, and each provided wlth a piston slidable therein, connecting rods diing staggered to correspond with the relative rectly connecting the first, second, third and position of said pairs of rods, and means for fourth pistons of each throw, respectively, firing the cylinders in pairs in two revolu- 10 tothe first, second, third and fourth throws, tions.

5 the bearing ends of said rods being respec- In witness whereof I have signed this tively interlocked in pairs and the pairs specification. juxtaposed and corresponding cylinders be- FREDERICK HENRY ROYCE. 

